UProject Summary Title: The Importance of Place of Birth in Determining Health and Mortality at Older Ages Substantial spatial inequalities in old age health and mortality outcomes are well documented. Previous studies have linked old age health to contemporaneous spatial context. However, by old age, over a third of the popu- lation has left their state of birth and an even greater share has left their county of birth, leaving the interpreta- tion of contemptuous links between geography and health clouded by endogenous mobility and disregarding the importance of childhood exposures in producing the spatial inequalities in health across the life course and into old age. Successfully unraveling the importance of life course exposures and decisions producing old age spatial inequalities has the potential to contribute to basic science as well as policy, but efforts have been ham- pered by a lack of large datasets with place of birth information. Our proposal takes advantage of newly avail- able data on place of birth for over 5 million Americans born across the early to mid 20PthP century combined with our team's interdisciplinary background merging the demography, economics, population health, and epidemi- ology of old age morbidity and mortality processes. UOur overall aim is to uncover the extent to which place of birth has contributed to old age health inequalities by birth cohort, race/ethnicity, sex, and educa- tional attainment in the US, and to explore the mechanisms underlying these relationshipsU. Our re- search team will leverage newly released and unique longitudinal data on millions of individuals across multiple datasets containing rich measures of health processes in old age and mechanisms of early disease exposures, cumulative contextual disadvantage, and life course mobility. Using these data, we will Upursue the following aimsU: (1) Aim 1: Create an ?Atlas of Birth Place Impacts on Mortality and Morbidity at Older Ages?, (2) Deter- mine the Influence of Birth Place on Health Disparities and Mortality Variation at Older Ages by sex, race/eth- nicity, and education and (3) Uncover mechanisms linking the relationship between place of birth and later health by focusing on mobility and early and cumulative exposures. Together, these aims will allow a paradigm shift in how we understand old age health processes by integrating life course and spatial analysis into large scale analyses of the patterns and mechanisms of old age health and mortality.